EP-A-O 196 132 describes 3-piperidinyl-1,2-benzoisoxa-zoles of formula (II) as having antipsychotic properties. ##STR3##
EP-A-O 037 265 describes 3-[(1-piperidinyl)-4H-pyrido-[1,2-a]pyrimidin-4-ones of formula (III) ##STR4## where R may be H, alkyl, OH, RO or CH.sub.2 OH in positions 2, 3 or 4 of the piperidine ring, useful as cardiovascular agents and which act on the central nervous system.
The compound of formula (I) of the invention differs from the known compounds in the presence of a double bond between the 3 and 4 positions of the piperidine ring and in its pharmacological activity.